Choose three fields of biology to describe and give one example of work done by scientist in each field you chose.

Entomology is the study of insects, some scientists travel to the far ends of the earth to discover new species of insects. for example, the new “Singing” Psyllid Species Found in Taiwan. (souce: entomologytoday)

herpetology is the study of reptiles and amphibians, scientists are still mapping out that category because theres much we still need to know about those cold-blooded animals for example theres a dangerous rumor that the suburban gardens are spreading a deadly disease in frogs (source: sciencedaily)

mammalogy is the study of mammals, this is where our species of 'homo sapiens' is included along with the marine mammals. scientists in this field are diving down into the depts to discover more about the ones in the oceans, currently theyre trying to save seal pups from the decreasing land-ice down in Antarctica (source: marinemammalcenter)

Iwould say overuse ( but not 100% sure ) in the u.s. we tend to overuse water by leaving it running, throwing it away, taking long showers, etc.